After a heart failure, for example a cardiac infarction or other reasons for the decrease in the performance of a heart, it is of essential importance for intensive care medicine to normalise and stabilise the cardiac function again as rapidly as possible. When for example the volume output of the heart is distinctly reduced as a result of a failure, it is particularly important to reliably and rapidly re-establish a corresponding peripheral blood flow in order to prevent secondary damage. The use of heart-lung machines basically allows the essential vital functions to be maintained. A specific adaptation to the respective actual requirements generally does not take place with such devices, however. Rather, conventional heart-lung machines are devices which, using external pumps, maintain a forced circulation of blood without systematically entering into the respective requirements of the heart which has been weakened or subjected to a failure.
In surgical interventions, particularly in the vein area, it has already been proposed to carry out retroinfusion, controlled by venous pressure, from or in veins of the body with the suction of fluid and return of the fluid via a pump. Conventional catheters are used here, the lumina of which allow a suction of fluid and via the lumina of which the return is made possible at a suitable site. Known devices, particularly for the retroinfusion of blood in coronary veins in the area of myocardial protection during a brief coronary artery closure within a cardiological intervention, are generally devised so that a balloon dilatation of an arteriosclerotically constricted coronary artery is carried out. In these cases, a compensation which is adapted to the intervention briefly taking place respectively can be carried out by the return of blood which has been drawn off in veins. For a continuous restitution of the full function of a heart, however, the criteria are not taken into account which would be relevant for the full function of the heart, and an intensive provision over a particular period of time is therefore not provided with such devices. At the same time, the provision of the other organs must also be maintained.
In the device known from AT 407 960 B for assisting the performance of a heart, fluid is removed from blood vessels via an external pump and is returned into blood vessels via a return catheter, in which the returned quantity of fluid is regulated as a function of measurement values, with a heart ventricle catheter being provided to obtain these measurement values. The known device comprised a heart ventricle catheter which is equipped in the cardiac chamber with sensors to measure the volume of fluid per unit of time, in which these sensors, in the introduced state of the heart ventricle catheter, lie in the cardiac chamber and these sensors are connected with an evaluation circuit in which the ratio of the diastolic volume to the systolic volume is evaluated per heartbeat or per unit of time in particular the discharge rate and/or the deviation of the volume conveyed per unit of time by the heart from a defined rated value is evaluated, for example the rated value, calculated from physically specific data for the cardiac output. The signal which is generated in this way is passed to the pump, via which fluid is withdrawn from the cardiac chamber and is recirculated as a function of the generated signal.